An automotive safety seat belt comprises a textile belt spanned between an anchor and a buckle assembly and over a person seated in the motor vehicle. In combined shoulder and lap belts the belt is spanned from an overhead anchor across the person's chest to the buckle, and also from a floor anchor over his or her lap to the same buckle assembly. The function of such safety belts is to prevent a person from being thrown forwardly in the event of a collision. The life-saving potential of such devices is enormous and has in fact been recognized to the extent that such safety belts are now required by law.
The principal objection to safety belts is, however, that after a collision or the like the safety-belt user might be trapped by the belt. In fact it has happened that a severe accident has made the buckle inoperative or inaccessible so that it becomes a very difficult operation to remove the user from the vehicle. The possibility of fire after an accident makes it imperative that the user be quickly freed from the constraining safety belt. Cutting the belt requires the user or the rescuer to have a good cutting instrument to sever the typically strong textile belt, and even then the user is exposed to the danger of being injured by such cutting instruments.